Accelerator pump



Oct. 11, 1932. F. H. HEITGER ACCELERATOR PUMP 2 Sheets-Sheet 1 Filed Aug. 12. 1929 WE :5 fiankH/Yizer Q/ QM F. H. HEITGER ACCELERATOR PUMP Oct. 11, 1932.

Fild Aug. 12. 1929 2 Sheets-Sheet 2 H Qv 5 155445555555:55555154551?! flan m Patented Oct. 11, 1932 PATENT OFFICE FRANK H. HEITGEB, OF FLINT, MICHIGAN ACCELERATOR PUMP Application filed August 12, 1929. Serial No. 385,342.

This invention relates to carbureters for internal combustion engines. In operating a carbureter for internal combustion engines to supply normal operating and running demands, the carburetor throttle is operated normally, slowly from a closed or lowest speed, or idle speed, to an open or wide open position, letting the speed of the motor increase in proportion to the i0 throttle opening, or as the throttle opens.

- However, sudden demands are put upon the carbureter, by sudderf opening of the throttle from a slow speed position. .Under such circumstances the main fuel feed of the carburetor may not be in action at all just prior to such action, (or at the slow speed). The carbureter'may be receiving its minimum supply of fuel distinct from this main supply at the time, and when the throttle is suddenly opened this minimum feed may cease instead of becoming greater. Therefore upon the sudden opening of the throttle, unless some means is installed to momentarily augment the fuel feed, the mixture supplied. to the motor will be too lean for an explosive mixture, due to the fact that under such conditions there is a sudden change of pressure on the main fuel feed, and this feed having first to start, and instantly supply the sudden inrush of air, which it does not, the mixture is lean, the main fuel supply being slow moving, or not moving at all at the instant of this augmented air feed.

Some means should be employed to forcibly start this fuel, and it should be done at the same time the air feed is augmented, and should not lag behind the air feed. After the fuel feed is forcibly started, there should be an augmented feed by force until the augmented or sudden air feed, subsides, or the air feed becomes normal, then there should be a feed that is more prolonged, but which is also an augmented feed, a modified force, then these feeds followed by a pure suction feed that is also an augmented feed. Finally after conditions become normal, a feed is had due to suction alone, and this feed, before fed to the air of the carbureter, may be impregnated or mixed with some air before its discharge into the carbureter.

It is an object of the presentinvention to provide a carbureter satisfying the above conditions of operation, and one that will be reliable and automatic in operation and simple and cheap to manufacture.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

This invention (in a preferred form) is illustrated in the drawings and hereinafter more fully described.

On the drawings:

Figure 1 is a central vertical section through a carbureter embodying one form of the features of this invention.

Figure 2 is a fragmentary detail of a slightly modified form of throttle control for the accelerating fuel supply.

Figure 3 is a section similar to that of Fig ure 1 incorporating an auxiliary well and I thus forming a modification thereof.

Figure 4 is a fragmentary detail of another modification wherein the manifold vacuum controls the accelerating mechanism.

Figure 5 is a section similar to Figures 1 and 3 modified so that the range of piston movement is such as to produce direct liquid displacement.

Figures 1, 2 and 4 thus relate to various embodiments of the operating mechanism, and Figures 1, 3 and 5 to variations of the fuel supply arrangements which are capable of use with the various operating mechanisms.

As shown on the drawings:

The various modifications of this inven-' tion have been illustrated as applied to a plain tube carbureter, although it is to be understood that the invention is not limited in its usefulness to carbureters of such a particular type since the present invention re- .lates to the provision of an increased fuel supply for accelerating and full power purposes as a supplement to the normal economical mixture range.- The illustrated carbureter comprises a body 10 having the usual constant level fuel supply chamber 11, to-

gether with an air inlet passage 12, which is provided with a choke valve 13, and a vertical mixture passage l l'terminating in a mounting flange 15. The mixture passage 14 contalns a venturi 16, at the throat of which is positioned the outlet 17 of a fuel nozzle 18. A throttle valve 19 mounted on a cross shaft 20 is also provided in the pas-- sage 14. The nozzle 18 is so proportioned as to be capable of delivering a considerable excess .of fuel over the maximum requirements of an economical mixture ratio, and is normally supplied with fuel through a passage 21 from an accelerating well 22 which in turn is supplied by a passage 23 containdelivery would lag behind the increased air flow due to an opening movement of the throttle, causing a pronounced temporary leanness in the mixture ratio which may in some cases be suflicient to stop the engine.

In order to supply additional fuel for maximum power a bypass passage 25 is formed around the orifice 2 1 and is restricted by a second restricted orifice 26. This bypass passage-is formed with a valve chamber 37 having a shouldered outlet 28 intothe accelerating well, a tapered valve 29 on a. stem 30 being urged upwardly into seating contact with the outlet shoulder, by means of a spring 31, thus normally closing the byass passage.

e varied to give any desired area of opening in proportion to a given range of movement of the valve stem. The upper end of the stem 30 is centered by an apertured disc 31 fixed in the accelerating well 22. A piston 33 is slideably mounted in the accelerating well" and may be provided with a packing ring 34 if desired. The piston is provided with a relatively small vent- 35 the size of which determines the speed of downward movement of the piston necessary to produce super atmospheric pressure on the fuel in the accelerating well.

. The piston may be operated from the throttle as shown in Figure 1 or by the drop in the intake manifold suction as shown in Figure 4, this suction drop or decrease being produced by an opening movement of the throttle. In either case the foregoing description applies to the different figures of the drawings.

In Figure 1 the throttle shaft 20'carries an operating lever 36 having an arm 37 against ing movement of the throttle.

The taper of the valve 29 may.

son with the throttle lever during the first part of the opening movement of the throttle. The lever 38 is freely pivoted on the throttle shaft and its outer end is connected by'a link .40 to the accelerator piston so that the latter is moved downwardly in the well by an open- A packing ring 41 is positioned in the well adjacent the valve stem guidedisc 32 and when the piston strikes this ring the lever 38 is held stationary regardless of further opening movement of the throttle, the packing ring serving to prevent air leakage when subjected to suction in the well.

In the operation of this embodiment of the invention, with the throttle closed as shown for idling, the piston will be up, pulled up by the operation of closing the throttle, by the arm 32 engaging lever 38, and while idling there will be atmospheric pressure above the fuel in the well 22, the air for this pressure .being admitted by thecalibrated vent 35.

Fuel will now' stand at dotted line X. Upon sudden opening of throttle, the piston 33 will drop and compress the air in the well and this air will momentarily act upon the surface of the fuel therein, and force fuel from ,the nozzle 17. At the same time some of this air is lost out of the vent 35. There is, however, due to the size of piston, its stroke, etc.. enough pressure created and acting on the fuel to inject fuel from nozzle 17 breaking the surface tension, etc., or in plain words, starting the fuel, so that it more nearly follows the air flow around nozzle 17 upon sudden throttle opening; this forced feed is followed by an induced suction flow from the well 22 to the nozzle, as is commonly understood, and when well 22 is empty or has exhausted its reservesupply, air is fed to the fuel by way of orifice 35 when the well is empty. Should the throttle be opened slowly, the super-atmospheric pressure will not be had in the well, in fact, itis not needed.

' where before with orifice 24 only in operation the fuel feed was for-economy only at a normal range of speed.

The purpose of this invention is to create 9 a super-atmospheric pressure in an auxiliary (air vented) fuel reservoir, to initially force fuel therefrom upon sudden opening of the throttle, and to at the same time open a valve that gives anadded fuel feed, and out the same nozzle, whether the piston or means is controlled by the throttle directly or indirectly, thus giving a rich feedwhen the throttle is suddenly opened, also opening up an extra fuel feed valve for power, and during the time said valve is closed, feeding an economical mixture.

It will be noted that there are no check valves, etc., anywhere in the fuel system operated by fluid flow, and that there is but one fuel passage leading to the mixing chamber of carbureter and that all the supply to and from the well is from this passage. I provide a definite means comprising a piston starting from above the normal fuel level to create the super-atmosphere pressure, and that the well is vented, this vent forming a means to calibrate a carbureter for a motor, the vent allowing practically all the air to escape when the throttle is slowly operated, and the vent allows the well to fill by gravity from the flow due to level in constant level chamber. In some of the objects of the invention I am not limited as to how the pressure is created, as long as it is done by sudden throttle opening.

Figure 3 resembles Figure 1 with the addition of an auxiliary reservoir 42 filled from the well 22 by the action of the piston 33, this reservoir having a calibrated vent 43 and being adapted to feed back the fuel after the cessation of movement of the piston 33. This reservoir is made smaller and higher than the well 22 in order that the fuel will be elevated higher therein to store up energy to maintain the extra supply of accelerating fuel after the accelerating well has lost its super-atmospheric pressure. The vent 43 for the auxiliary reservoir may desirably be so made that its calibration may be varied to suit individual engines, as the size of the ventgoverns the rate of filling and emptying of the reservoir.

Figure 5 closely'resembles the structure of Figure 3 with the exception that the accelerating well is intended to operate without air pressure, the piston 33 being lowered to the fuel level and the valve stem disc 32 and piston stop 41 being positioned below the fuel level so that the piston acts directly against the fuel and the vent 35 therein passes fuel into the cup like hollow of the piston, which fuel flows back into the well again after the piston returns to its normal position.

The suction controlled accelerating piston of Figure 4 may be substituted for the throttle controlled piston of the other figures. This modification comprises a spring 45 acting above the piston 33 to force the same downwardly. The upper end of the well 22 is closed and provided with a vent 46opening into a passage 47 one end of which opens into the mixture passage 14, above the closed position of the throttle 19, and is restricted by an orificeplug 48. With this arrangement the well above the piston 22 is'subjected to latethe admission of air from the chamber 49 to the passage 47. This air bleed into the passage 47, in cooperation with the orifice plug 48 serves to reduce the effective suction acting to hold back the piston, so that a suitable adjustment of the needle valve 51 will serve to vary the suction on the piston and will thus determine the point at which the piston drops relative to the opening movement of the throttle, which varies the manifold suction. The suction restrained piston functions in much the same manner as regards imposing pressure upon the fuel in the well 22 although the central vent in the piston is omitted because of its effect on the operation of the piston by suction.

It will thus be seen that I have provided an improved and simplified carbureter embodying an accelerating fuel supply responsive to the rapidity and extent of throttle opening and adapted to maintain the supply of accelerating fuel after the initial throttle movement has'ceased.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than necessitated by the prior art.

I claim as my invention:

1. In a carbureter for internal combustion engines a combustible mixture passage, a

, throttle valve therein, means for feeding fuel directly to said passage including a fuel well, an air vent for said fuel well to feed air into said fuel feeding means when said well is emptied, a bypass fuel passage also feeding fuel to said mixture passage, a valve controlling said bypass passage, means cooperating with said well and valve to form a superat mospheric pressure on the fuel in said well and to open the bypass valve upon an opening movement of the throttle.

2. In a carbureter for internal combustion engines a: combustible mixture passage, a throttle valve therein, means for feeding fuel directly to said passage including a fuel Well, an air-vent for said fuel well to feed air into said fuel feeding means when said well is emptied, a bypass fuel passage also feeding fuel to said mixture passage, a valve controlling said bypass passage, a piston cooperatnection permittin 3. In a. carbureter for internal combustion engines including a combustible mixture passage having a throttle therein, a fuel nozzle, means for supplying fuel thereto including an accelerating well, a piston slidable in said well, a bypass fuel passage around said well avalve controlling said bypass, linkage yieldingly connecting said piston to the throttle to move the piston in the well downwardly during the first part of the opening movement of the throttle, the yielding confurther opening movement of the thrott e after the piston reaches the limit of its effective travel and said piston being adapted to open said bypass valve at the limit of its downward motion.

4. In a carbureter for internal combustion engines including a combustible mixture passage having a throttle therein, a fuel nozzle, means for supplying fuel thereto including an accelerating Well, a piston slidable in said well, an auxiliary fuel reservoir connected to the well to receive fuel displaced therefrom by the movement of said piston and to continue the fuel discharge after the piston stops its downward movement, and linkage yieldingly connecting said piston to the throttle to move the piston in the well downwardly during the first part of the opening movement of the throttle, the yielding connection permitting further opening movement of the throttle after the its effective travel.

5. In a carbureter for internal combustion engines including a combustible mixture passage having a throttle therein, a fuel nozzle, means for supplying fuel thereto including 7 an accelerating well, a piston slidable in said well, an auxiliary fuel reservoir connected to the well to receive fuel displaced therefrom by the movemcnt'of said piston and to continue the fuel discharge after the piston stops its downward movement and linkage yieldingly connecting said piston to the throttle to move the piston in the well downwardly during the first part ofthe opening movement of the throttle, the yielding connection permittin further opening movement of the throttle after the piston reaches the limit of its effective travel and a vent in said auxiliary reservoir for controllin the time'of flow of fuel into and out of sai reservoir;

In testimony whereof I have hereunto subscribed my name at Flint, Genesee County,

Michigan.

FRANK H. HEITGER.

piston reaches the limit of 

